1. Field of the Invention
The present invention relates to the field of bioinformatics. In particular, the present invention relates to computer systems, methods, and products for the storage and presentation of data resulting from the analysis of microarrays of biological materials.
2. Related Art
Research in molecular biology, biochemistry, and many related health fields increasingly requires organization and analysis of complex data generated by new experimental techniques. The rapidly evolving field of bioinformatics addresses these tasks. See, e.g., H. Rashidi and K. Buehler, Bioinformatics Basics: Applications in Biological Science and Medicine (CRC Press, London, 2000); Bioinformatics: A Practical Guide to the Analysis of Gene and Proteins (B. F. Ouelette and A. D. Bzevanis, eds., Wiley & Sons, Inc.; 2d ed., 2001), both of which are hereby incorporated herein by reference in their entireties. Broadly, one area of bioinformatics applies computational techniques to large genomic databases, often distributed over and accessed through networks such as the Internet, for the purpose of illuminating relationships among gene structure and/or location, protein function, and metabolic processes.
The expanding use of microarray technology is one of the forces driving the development of bioinformatics. Spotted arrays, such as those made using the Affymetrix® 417™ or 427™ Arrayer from Affymetrix, Inc. of Santa Clara, Calif., are used to generate information about biological systems. Also, synthesized probe arrays, such as Affymetrix® GeneChip® arrays, have been widely used to generate unprecedented amounts of information about biological systems. For example, the GeneChip® Human Genome U133 Set (HG-U133A and HG-U133B) is made up of two microarrays containing over 1,000,000 unique oligonucleotide features covering more than 39,000 transcript variants that represent more than 33,000 human genes. Experimenters can quickly design follow-on experiments with respect to genes, EST's, or other biological materials of interest by, for example, producing in their own laboratories microscope slides containing dense arrays of probes using the Affymetrix® 417™ or 427™ Arrayer, or other spotting device.
Analysis of data from experiments with synthesized and/or spotted probe arrays may lead to the development of new drugs and new diagnostic tools. In some applications, this analysis begins with the capture of fluorescent signals indicating hybridization of labeled target samples with probes on synthesized or spotted probe arrays. The devices used to capture these signals often are referred to as scanners, an example of which is the Affymetrix® 428™ Scanner.
There is a great demand in the art for methods for organizing, accessing and analyzing the vast amount of information collected by scanning microarrays. Computer-based systems and methods have been developed to assist a user to obtain, analyze, and visualize the vast amounts of information generated by the scanners. These commercial and academic software applications typically provide such information as intensities of hybridization reactions or comparisons of hybridization reactions. This information may be displayed to a user in graphical form. In particular, data representing detected emissions conventionally are stored in a memory device of a computer for processing. The processed images may be presented to a user on a video monitor or other device, and/or operated upon by various data processing products or systems.
In particular, microarrays and associated instrumentation and computer systems have been developed for rapid and large-scale collection of data about the expression of genes or expressed sequence tags (EST's) in tissue samples. The data may be used, among other things, to study genetic characteristics and to detect mutations relevant to genetic and other diseases or conditions. More specifically, the data gained through microarray experiments is valuable to researchers because, among other reasons, many disease states can potentially be characterized by differences in the expression levels of various genes, either through changes in the copy number of the genetic DNA or through changes in levels of transcription (e.g., through control of initiation, provision of RNA precursors, or RNA processing) of particular genes. Thus, for example, researchers use microarrays to answer questions such as: Which genes are expressed in cells of a malignant tumor but not expressed in either healthy tissue or tissue treated according to a particular regime? Which genes or EST's are expressed in particular organs but not in others? Which genes or EST's are expressed in particular species but not in others? How does the environment, drugs, or other factors influence gene expression? Data collection is only an initial step, however, in answering these and other questions. Researchers are increasingly challenged to extract biologically meaningful information from the vast amounts of data generated by microarray technologies, and to design follow-on experiments. A need exists to provide researchers with improved tools and information to perform these tasks.